110 lines
1.9 KiB
Racket
110 lines
1.9 KiB
Racket
#lang scribble/manual
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@(require (for-label racket))
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@title{FBSineL}
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Feedback sine with chaotic phase indexing@section{categories}
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UGens>Generators>Chaotic
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@section{related}
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Classes/FBSineC, Classes/FBSineN
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@section{description}
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A linear-interpolating sound generator based on the difference equations:
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teletype::
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x(n+1) = sin(im * y(n) + fb * x(n))
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y(n+1) = (a * y(n) + c) % 2pi
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::
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This uses a linear congruential function to drive the phase indexing of a sine wave. For
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@racketblock[ im = 1 ::, ]
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@racketblock[ fb = 0 ::, and ]
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@racketblock[ a = 1 :: a normal sinewave results.
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sclang code translation:
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]
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@racketblock[
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(
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var im = 1, fb = 0.1, a = 1.1, c = 0.5, xi = 0.1, yi = 0.1, size = 64;
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plot(size.collect { xi = sin((im * yi) + (fb * xi)); yi = (a * yi + c) % 2pi; xi });
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)
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::
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]
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@section{classmethods}
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@section{method}
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ar
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@section{argument}
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freq
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Iteration frequency in Hertz
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@section{argument}
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im
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Index multiplier amount
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@section{argument}
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fb
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Feedback amount
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@section{argument}
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a
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Phase multiplier amount
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@section{argument}
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c
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Phase increment amount
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@section{argument}
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xi
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Initial value of x
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@section{argument}
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yi
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Initial value of y
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@section{examples}
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@racketblock[
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// default initial params
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{ FBSineL.ar(SampleRate.ir/4) * 0.2 }.play(s);
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::
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]
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@racketblock[
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// increase feedback
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{ FBSineL.ar(SampleRate.ir, 1, Line.kr(0.01, 4, 10), 1, 0.1) * 0.2 }.play(s);
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::
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]
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@racketblock[
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// increase phase multiplier
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{ FBSineL.ar(SampleRate.ir, 1, 0, XLine.kr(1, 2, 10), 0.1) * 0.2 }.play(s);
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::
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]
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@racketblock[
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// modulate frequency and index multiplier
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{ FBSineL.ar(LFNoise2.kr(1, 1e4, 1e4), LFNoise2.kr(1,16,17), 1, 1.005, 0.7) * 0.2 }.play(s);
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::
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]
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@racketblock[
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// randomly modulate params
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(
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{ FBSineL.ar(
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LFNoise2.kr(1, 1e4, 1e4),
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LFNoise2.kr(1, 32, 33),
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LFNoise2.kr(1, 0.5),
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LFNoise2.kr(1, 0.05, 1.05),
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LFNoise2.kr(1, 0.3, 0.3)
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) * 0.2 }.play(s);
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)
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::
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]
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